package simpleStructure;


public class Array<E> {

    private E[] data;
    private int size;

    public Array(int capacity) {
        capacity = capacity < 16 ? 16 : capacity;
        data = (E[]) new Object[capacity];
        size = 0;
    }

    public Array() {
        this(16);
    }

    public int getSize() {
        return size;
    }

    public int getCapacity() {
        return data.length;
    }

    // 向size 位置添加元素
    public void addLast(E e) {
        add(size, e);
    }

    public void addFirst(E e) {
        add(0, e);
    }

    // 向指定的位置插入元素
    public void add(int index, E e) {
        if (index > size || index < 0) {
            throw new IllegalArgumentException("Add fail; Require index >=0 and index <= size");
        }
        if (size == data.length) {
            resize(data.length * 2);
        }
        for (int i = size; i > index; i--) {
            data[i] = data[i - 1];
        }
        data[index] = e;
        size++;
    }


    public E get(int index) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("get fail; index is illegal");
        }
        return data[index];
    }

    public void set(int index, E e) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("get fail; index is illegal");
        }
        data[index] = e;
    }

    public boolean contains(E e) {
        for (int i = 0; i < size; i++) {
            if (data[i].equals(e))
                return true;
        }
        return false;
    }

    public int find(E e) {
        for (int i = 0; i < size; i++)
            if (data[i].equals(e))
                return i;
        return -1;
    }

    public void removeElement(E e) {
        int index = find(e);
        if (index != -1) {
            remove(index);
        }
    }

    public E remove(int index) {
        if (index < 0 || index >= size) {
            throw new IllegalArgumentException("delete fail; index is illegal");
        }
        E datum = data[index];
        for (int i = index + 1; i < size; i++) {
            data[i - 1] = data[i];
        }
        size--;
        data[size] = null;
        if (size < data.length / 4 && data.length > 16) {
            resize(data.length / 2 );
        }
        return datum;
    }

    public E removeFirst() {
        return remove(0);
    }

    public E removeLast() {
        return remove(size - 1);
    }
    public boolean isEmpty(){
        return size == 0;
    }

    public E getLast(){
        return get(size - 1);
    }

    public E getFirst(){
        return get(0);
    }

    @Override
    public String toString() {
        StringBuilder res = new StringBuilder();
        res.append(String.format("Array size=%d, capacity=%d, [", size, data.length));
        for (int i = 0; i < size; i++) {
            res.append(data[i]);
            if (i != size - 1) {
                res.append(",");
            } else {
                res.append("]");
            }
        }
        return res.toString();
    }

    private void resize(int newCapacity) {
        E[] newData = (E[]) new Object[newCapacity];
        for (int i = 0; i < size; i++) {
            newData[i] = data[i];
        }
        data = newData;
    }
}
